The Vampiress is an enemy from Final Fantasy IV -Interlude-. Always appearing alongside either Blood Bats or Vampire Bats, she is a potentially dangerous enemy, due to her use of Thundara, Bloodfeast, which inflicts damage and Sap on a character, and Glare, which inflicts Confuse.
An effective strategy would be for Porom to use her Cry ability, which attempts to inflict Confuse on all enemies. This way, the Vampiress and the bats will use Bloodfeast on each other, which will not remove Confuse as it is classed as a magic attack. This way, the player can defeat them without being harmed.
Vampires are mythological or folkloric beings who subsist by feeding on the life essence, generally in the form of blood, of living creatures. Although vampiric entities have been recorded in many cultures, and may go back to "prehistoric times", the term vampire was not popularized until the early 18th century.